Paint brush



FIG. 1 is a perspective view of a paint brush, showing our new design;

FIG. 2 is a top (or bottom) plan view thereof; and,

FIG. 3 is a side elevation view thereof.

The broken lines immediately adjacent the shaded areas represent the bounds of the claimed design and all of the other broken lines illustrate portions of the article. None of the broken lines form part of the claimed design. 

The ornamental design for a paint brush, as shown and described. 